Launch vehicles use combustion of propellants consisting of oxidiser and fuel for deriving the energy. Air breathing propulsion systems use atmospheric oxygen, which is available up to about 50 km of earth’s surface to burn the fuel stored on-board thereby making the system much lighter, more efficient and cost effective. Air breathing propulsion is a solution for a powered long return cruise flight necessary for reusable launch vehicles. The collection and use of air involves challenges as the launch vehicle speeds through atmosphere at supersonic speeds. This calls for the development of ramjet or scramjet (supersonic combustion ramjet) technologies.

The Dual Mode Ramjet (DMRJ), the ramjet-scramjet combination, is currently under development, which will operate during the crucial Mach 3 to Mach 9 ascend flight of the launch vehicle. An Advanced Technology Vehicle (ATV) based on sounding rocket was developed for DMRJ Flight Technology demonstration and one developmental flight, ATV-D01, was conducted. Further developmental flights are planned in the near future.